1. Field of the Invention
The present general inventive concept relates to a backlight unit and a liquid crystal display having the same. More particularly, the present general inventive concept relates to a backlight unit to improve efficiency and reliability through an interconnection structure, which applies power to a printed circuit board on which a light emitting diode is mounted, and a liquid crystal display having the same.
2. Description of the Related Art
A liquid crystal display (LCD) displays images using electrical and optical properties of liquid crystal. Since the LCD has advantages of slimness, lightweight, low power consumption, and low driving voltage as compared with other display apparatuses, the LCD has been extensively employed in various industrial fields.
The LCD includes a liquid crystal display panel, in which liquid crystal is interposed between two transparent substrates and voltage is usable with the liquid crystal to change a direction of liquid crystal molecules to optically display images, and a backlight assembly for providing light to the liquid crystal display panel.
A CCFL (Cold Cathode Fluorescent Lamp), an EEFL (External Electrode Fluorescent Lamp), and an FFL (Flat Fluorescent Lamp) are used as light sources of the backlight assembly. However, the CCFL represents limitations in terms of high definition, light weight, slim structure and compact size, so an LED (Light Emitting Diode) has been recently used as the light source of the backlight assembly because the LED represents improved performance such as high brightness, long life span, and high color purity. In addition, as restriction on dumping of dangerous substances, such as mercury, have become widely enforced, the CCFL is less used, and the LED, which is an environmentally friendly device, is widely used instead of the CCFL.
The backlight assembly having such an LED as the light source is classified into a direct-type backlight assembly and an edge-type backlight assembly according to the arrangement of the LED and the type of the light guide plate. The direct-type backlight assembly having the LED has a structure in which the LED is disposed in front of the backlight assembly, so the direct-type backlight assembly has a difficulty in achieving slimness and requires a large number of LEDs, increasing the manufacturing cost.
In contrast, the edge-type backlight assembly has a structure in which the LED is mounted at both sides of the backlight assembly and light is introduced into the front surface of the backlight assembly through a light guide plate, so the edge-type backlight assembly may have a thickness smaller than that of the direct-type backlight assembly, thereby realizing the slimness structure.
A backlight unit provided with the LED includes a box-shape bottom chassis having an open upper surface to sequentially receive a reflection plate, the light guide plate, and optical sheets therein. In addition, a plurality of LEDs mounted on the printed circuit board are provided adjacent to a side of the light guide plate in the backlight unit.
The LEDs are connected to an inverter board, which is mounted on a rear surface of the bottom chassis, through a wire or an interconnection to receive drive voltage, so the LEDs emit light.
In general, the printed circuit board, on which the LEDs are mounted, is connected to the interconnection inside the bottom chassis, so extra space for such a connection is required. In addition, when the backlight assembly is coupled to the bottom chassis, short circuit or ground failure of the interconnection connected to the printed circuit board may occur. In this case, the backlight assembly needs to be separated from the bottom chassis and then connected to the bottom chassis again. Accordingly, the assembling work is complicated and the working time is increased.